Patient registration is routinely performed in image-guided surgery to establish a required spatial transformation between anatomies of interest and the corresponding preoperative images. The accuracy of an image-guidance system directly depends on the accuracy of the patient registration based on which image navigation is provided.
Currently, patient registration is performed using fiducials either affixed to skin or implanted in bone. Bone-implanted fiducials provide the most accurate registration, but are invasive to the patient and result in discomfort to the patient. By contrast, skin-affixed fiducials are less accurate, but they are noninvasive and are therefore, more commonly employed. Unfortunately, fiducials have to remain on the skin or in the bone of the patient from the time the preoperative images are acquired until patient registration is finished, which is usually hours.
Fiducial-based registration requires manual identification of fiducials in the operating room as well as in the image space (although some commercial systems are able to identify fiducial locations automatically in the image space), which accounts for a significant amount of operating room time. As an example it typically takes around ten minutes or more to perform patient registration, and even more when patient registration has to be repeated. In addition, accurate identification of fiducials also requires sufficient training.
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.